I work with batteries, it is almost always the cost of setting up a factory for a new process is just too high. Especially the first factory where you need new machines that don't exist yet.

My company is actually developing new lithium-metal battery chemistry that uses existing process for manufacturing, this is much more cost-effective and lower risk. You can just slightly retool an existing lithium-ion factory to pump out these new batteries.

Large-scale lithium-ion ever became a thing because Sony pumped a ton of R&D into walkmans.